It is known that optical discs of the type commercially referred to as "compact discs" and normally used for recording and reproducing sounds and/or images and also for storing data for computers, are generally packaged into cases of transparent plastic material each of which is essentially defined by a housing portion on which a lid portion to be snap-closed is hinged like a book.
More specifically, in one widely used type of case, the compact disc is removably engaged on a so-called "tray" which in turn is mounted by restrained coupling to the housing portion of the case after introducing into the housing portion one leaflet generally including lyrics and/or illustrations (e.g., referring to data or recorded music provided on the compact disc).
A booklet containing further information about the record album and/or the recorded data is also placed in the lid portion. This booklet is engaged with the lid portion by sliding the booklet between the inner surface of the lid portion and appropriate retaining tabs projecting from the inside surface of the lid portion so as to retain the booklet at its opposite edges.
There are several other types of cases distinguishable from the case previously described. For example, in one such prior case, a tray is adapted to receive two compact discs on its opposite faces, while other cases are completely devoid of the tray.
In cases in which there is no tray, the compact disc is removably engaged on retaining lugs directly formed in the housing portion of the case. In this type of compact disc case, the previously mentioned leaflet and booklet are replaced by a single sheet usually referred to as a "cover". Such a cover is engaged internally of the lid portion by insertion of one of its bent edges in a pocket-like seat formed along the pivot edge of the lid portion on the housing portion.
In order to achieve a finished package compact disc, the required operations for packaging compact discs into the respective cases are usually performed with the aid of automatic apparatus, essentially provided with a plurality of work stations suitably distributed along a feed line.
With such an automatic apparatus, the individual cases are received from a feeding magazine of a case feeding unit and are engaged sequentially by a case separation member which causes the cases to progress stepwise along the feed line.
During this movement along the feed line, each case first encounters an opening station wherein, upon the action of a grasping member provided with a suction cup at an end of appropriate mechanical linkage, the case lid portion is moved, by a 180.degree. overturning, from a closed condition, wherein the lid portion lies upon the housing portion of the case, to an open condition, wherein the lid portion extends in a coplanar relation with the housing portion.
Arranged downstream of the opening station is another work station, where the above-mentioned leaflet is introduced and inserted into the housing portion of the case. To achieve this result, an appropriate leaflet insertion mechanism is provided to receive the individual leaflets from a leaflet collection magazine in which the leaflets are arranged in the form of a stack. Each leaflet is then introduced into the housing portion by the insertion mechanism after the leaflet has been suitably shaped by means of an appropriate bending mold.
Subsequently, the cases are transferred to two further work stations wherein a tray is inserted into the housing portion of each case and then in succession engaged in the case by a restrained coupling. In another work station, one booklet is disposed on the inner face of the case lid portion, and afterwards each case is transferred to a further work station wherein a compact disc is brought into engagement with the tray disposed in the housing portion. Each case along the feed line is finally transferred to a closing station wherein, with the aid of a pusher element operated by an appropriate driving mechanism, the lid portion is moved from the open condition to the closed condition.
In the packaging apparatus of the above-described type, movement of the grasping members and pusher elements located in the opening and closing stations and operation of most of the movable members provided in all of the work stations are achieved by a mechanical transmission.
As a result, since it is necessary to impart a 180.degree. rotation to the lid portion in order to move it between the closed and open conditions, the mechanical linkages for transmitting all of these movements is necessarily of a very complicated structural construction. In addition, these mechanical linkages must operate in a very precise manner in that the compact disc cases are usually made of a plastic material which is easily breakable.
As a result thereof, the mechanical components of the prior compact disc packaging apparatus for opening and closing the cases are themselves very complicated in nature, thereby leading to higher production costs and also enhanced servicing and start-up costs.
In addition, the above-described apparatus of the known art are very bulky and their construction involves high costs because each of the operations provided in the packaging cycle requires the presence of a specific work station along the feed line. Besides the work stations for respectively carrying out the insertion of the leaflets, trays, booklets and compact discs, further work stations must be provided although they are likely to be often inactive. In fact, such stations are equipped with the appropriate devices only in case of need, for example, for performing either the insertion of a second compact disc if trays intended for supporting two compact discs are used, or for the insertion of the so-called "cover" if cases adapted to directly receive the compact discs are used (that is, cases which do not require insertion of the tray, the leaflet and the booklet).